Sound-reproducing apparatus



April 26,1927. 1,625,844

c. A. BRIGHAM SOUND REPRODUCING APPARATUS Filed Nov. 2, 1926 2 Sheets-Sheet l A TTORNEY l9 7 Apnl 26 2 c. A. BRIGHAM SOUND REPRODUQING APPARATUS Filed Nov. 2. 1926 2 Sheets-Sheet 2 IN V EN TOR.

1-: Era-i I? HI I Till I I II uni ' Patented Apr. 26, 1927.

UNITED STATES 1,625,844 PATENT. OFFICE.

CYRIL A. BRIGEAM, OF EAST ORANGE, NEW JERSEY, ASSIGNOR- TO BRANDES LABORA- TORIES, INC., 01 NEWARK, NEW JERSEY, A CORPQKATION OF NEW JERSEY.

SOUND-BEPRODUCING APPARATUS.

Application filed November 2, 1926. Serial No. 145,809.

One of the 0b]8CtS of my invention is to provide a sound reproducer in which an electroma netic driving mechanism is provided wit a flat driving element which substantially floats between the pole pieces v of the electromagnetic driving mechanism magn for imparting vibrations to a sound reproducin diaphragm which directly connects vto a et driving element.

Another object of my invention is to provide an electroma etic sound reproducer having a jfiat driving element therein for imparting vibrations to a diaphragm which is substantially free floating at the edge thereof.

Another object of my invention is to provide a sound reproducer wherein a sound reproducing diaphragm extends angularly in all directions from a flat vibratory element which is suspended within a variable etic field whereby mechanical vibrations initiated in the said flat vibratory element may be directly transferred to said sound reproducing diaphragm.

M invention will be more clearly understoo by reference to the following specification and theaccompanying drawings in which: X

Figure 1 is an elevational view of the electromagnetic driving element and sound reproducing diaphragm of my invention; Fig. 2 is a plan view partia 1y broken away and illustrated in cross-section showing the parts of the sound reproducing system of my invention; Fig. 3 is a cross-sectional view taken through the reproducer of my invention and showing the arrangement of the driving element with respect to the sound reproducing diaphragm; Fig. 4 is a cross-sectional view with the sound reproducing element shown partially in elevation and in cross-section on line 4-4 of Fi 3; and Fig.- 5 is a perspective view of the parts of the connecting means which are interposed between the sound reproducing diaphragm and the electromagnetic driving element.

Referring to the drawings in detail reference character 1 designates a panel member which is apertured to permit a sound reproducing diaphragm to float therein with a rubber membranes 2 in the form of an annular ring disposed between the peripheral edge 5 on sound reproducing diaphragm 3 and apertured panel 1. The

sound reproducing diaphra m is formed of relatively stiff materialwhich is dished or gathered at its center into a flattened portion at 4 with a pair of parallel extending lip portions 5 and 6 prO ecting in a plane parallel'to the axis of said sound reproducing diaphragm. The lip members 5 and 6 grip opposite faces of a flat coil support 7 which carries windings 8 and 9 on opposite sides thereof. extremely li ht in weight by reason of aperture's 10 an 11 and the small mass of the material. Projections 11 and 12 are formed on the coil support 7 and these are secured in the buttons 14 and 15 which are carried by the spider member 16 which is suspended. from the panel member 17. The electromagnetic sound reproducer includes a frame structure 25 which supports the panel members 17 and 18 on opposite sides thereof with the electromagnetic system 21 and 22 disposed therebetween. Conductive plate members 23 and 24 are secured over the pole pieces forming a gap within which the windings 8 and 9 are arranged to be laterally vibrated. Vibrations imparted to the windings 8 and 9 impart vibratory mo- The flatcoil support 7 is tion to the coil support 7, which in turn port 7 and attached at opposite ends to the sides of the apertured panel 18. The strip members 19 and 21 are constructed of such material as to be substantially rigid against movement in a direction parallel to the axis of pole pieces 21 and'22 while being exv tremely flexible for movement of coils 8 and 9 in a path normal to the axes 015 the pole pieces. I may employ strips of celluloid forthe members 19 and 20 and for the spider 16. whichmaterial possesses the property; of rigidity inthe direction of its length while being'extremel flexible in a directlon nor mal to its sur ace. v

Thevibratory system is substantially suspended between spider 16 at one end and by the strip members 19 and 20 at the opposite end, the sound reproducin diaphragm -3 being supported from the 0011 support 7 substantially in the form of a cantilever, the eripmheral edge .5 of the sound reproducin 'ap ragm 3 being substantially free an unconfined inasmuch as 'the materialv 2 is extremely light and flexible and may itself possess the roperty of stretching by reason,

of. its resi lent characteristics. In man cases I leave a substantial amount of slac in the annular ring member 2 preventing injury to the peripheral edge of the-sound re reducing diaphragm 5.-

ile I have described my invention in one of its-preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims. What I claim as new and desire to secure i by Letters Patent of the United States is o es follows:

1. An electromagnetic sound reproducer comprising an electromagnetic driving mechanism, a vibratory member actuated by said mechanism, a sound reproducing diaphragm, said diaphragm being substantially dished at the center thereof and havmg a pair of co-extensive parallel lip portions secured to said vibratory member whereby vibrations initiated in said vibratory member are transferred throu h said lips to said sound reproducing diap iragm.

2. An electromagnetic sound reproducer comprising an electromagnetic mechanism including a set of pole pieces, an element capable of vibration suspended between said pole pieces, a sound reproducing its center, said diaphragm terminating in a diaphragm which is substantially dished at pair of flat parallel tapered lip members,

said lip members being attached to opposite sides of said vibratory element whereby driving saidmember in such manner that mechani-"- riphery and being dished at the center thereof and terminating in a pair of flat parallel lip members, said lip members being spaced one from the other and secured to opposite sides of said flattened projection whereby vibrationsinitiated in said vibratory member may be transferred to said sound reproducin diaphragm.

v5.?[11 an electromagnetic sound reproducer, an electromagnetic driving mechanism including sets of pole pieces directed toward each other, a vibratory element sus pended between said pole pieces in a plane normal to the axis thereof and free to vibrate between said pole pieces with substantially no iiiertia, said vibratory element terminating in a flattened extension project-v ing beyond the limits of said pole pieces, a sound reproducing diaphragm iaving a substantially circular outer periphery and converging toward said flattened extension said diaphragm terminating m a pair oi fiat parallel extending lip portions secured to opposite sides of said flattened extension whereby vibrations initiated in said vibratory. element may be transferred to said sound reproducing diaphragm.

6. An electromagnetic sound reproducer comprising a driving mechanism includin sets of pole pieces directed toward eac other, a vibratory element mounted between said pole pieces said vibratory element comprising a flat coil support and a pair of windings carried on said support, a sound reproducing diaphra m having a substantially rounded perip liery, said diaphragm converging toward said coil support and enveloping opposite sides thereof, and means for suspending said coil support at opposite ends in a position in which said windings are free to vibrate in a'plane normal to the axes of said pole pieces for transferring vibrations to'said sound reproducing diaphragm.

7. Anelectromagnetic sound reproducer comprising an electromagnetic driving mechanism including a plurality of sets of pole pieces directed toward each other, a fiat coil support, a pair of windings carried by said coil support, flexible strip members se cured to opposite ends of said coil support in planes normal to the axis of said coil support whereby said coil support is free to v1 rate in a plane normal to the axis of said pole whereby vibration initiated in said wind pieces, a sound reproducing diaphragm subings may be imparted to said sound reprom stantially rounded at its periphery and' duoing diaphragm.

convei'ging toward said coil support, said In testimony whereof afilx my signa-' 5 sound reproducing diaphragm terminating ture, I V o in a pair of fiat parallel extending lip meme o bets on opposite sides of said coil support CYRIL L BRIGHAM. 

